1. Field of the Invention
The present invention relates to a radio switching apparatus which achieves reduced consumption of electric power.
2. Description of the Related Art
In recent years, various radio application systems, for example, electric-power or gas meter reading systems using radio, or IC card systems using radio, have been researched. Here, the meter reading system using radio is designed to detect an amount of electric power, gas or the like used by driving a meter reading apparatus using radio in an automobile without a meter reading person going to the place where the meter is disposed.
Meanwhile, the major problem in such a system is consumption of standby electric-power. That is, in order to drive, for example, the meter reading apparatus using radio, it is necessary to continually have the meter reading apparatus in a standby state (a state in which radio waves can be received). For this purpose, a receiving circuit must continually be in an active state. However, if the receiving circuit is continually in an active state, electric power consumption increases. When, for example, the meter reading apparatus is driven by a small battery, the service life of the battery is extremely short because of the electric power consumption of the receiving circuit. In particular, in the case of an apparatus which is driven once per month like a meter reading apparatus, such wasteful consumption of electric power by the receiving circuit is very undesirable.